If you drawn empty shapes using drawing tools, when you’re ready to start defining areas for text and graphics, you may need to redefine the placeholders for either text or graphics, if the ones you've designed are not of the right type.
To convert any placeholder into a text frame
On the Tools menu, point to Replace objects, and then select Replace with Text frame.
To convert any placeholder into a graphics frame
On the Tools menu, point to Replace objects, and then select Replace with Image.
Note: When a frame contains text or graphics, if you redefine it, it will loose its content.
See also
Using placeholders to design pages
Convert an irregular frame into placeholder, keeping the shape